In a shipping department, for instance of a warehousing operation that assembles and ships orders, it is standard to include with each order a substantial literature insert. The orders themselves are assembled and moved along on a transport belt in individual piles of articles, mailing tubes, bottles, blister packs, or the like each constituting a single order. The literature-inserting apparatus puts a literature pack, typically all folded together, on the belt in front of each such pile so that as same is pushed into a carton the literature is pushed in first.
In the standard system described in German patent document 3,118,209 the literature is prepared by a folding machine which folds up the literature packs and delivers the thus produced folded literature inserts one at a time by means of a pair of belts to a transfer location. The belts have stretches running parallel to and in contact with each other to define a travel path. The folded literature packs travel to the downstream end of this path, where the two belts pass over rollers that deflect them oppositely away from each other at the transfer location. Here the folded literature inserts are gripped by transfer clips as they emerge from between the belts at the downstream end of the path. The transfer clips, which are carried on a transfer conveyor, then pass off the literature inserts to the main conveyor belt on which the orders are moving, with of course everything synchronized to put one such insert with each order.
The folding-machine belts normally move somewhat faster than the transfer conveyor and the literature inserts emerge from the folding machine at the transfer location in a direction that corresponds to the direction the transfer clips are moving in as they pass the transfer location. The clips are open backward in their direction and the higher speed of the folding-machine belts cause the inserts to be pushed from behind into these transfer clips. This requires that the operation of the folding machine and of the transfer conveyor, which is set up to open and close the clips as they pass the transfer location, be extremely accurately synchronized with each other. The literature packs must be delivered at exactly the right time to the transfer location or the handoff is missed and/or the machine is jammed. Thus if a literature pack slips as it is being transported, the whole system can be brought down.
Another disadvantage is that it is difficult to crowd all the necessary structure in at the transfer location. The inserts move in a transfer plane as they are picked up by the transfer clips. This plane must inherently be laterally offset somewhat from and parallel to the path of the main order-conveying belt, and the offset is at least equal to the diameter of one of the downstream deflecting rollers of the folding machine. Positioning all this structure at this location is a problem.